shalou

沙漏 (shālòu in Chinese) means hour glass. I built it because I wanted a timer for tea brewing, cooking, and Pomodoro working.

I wanted it to be

• simple and 渋い
• autonomous
• quick and straight-forward to use
• no cell phone
• no beeping or vibrating

When time’s up, it flashes.

It has three buttons: enter, up, and down. A list of commonly used periods between 10 seconds and 90 minutes is stored and can be cycled through quickly. A faint yellow LED on the backside breaths every second. The timer switches off automatically if it’s not being used. After wake-up, it’s in the same state as before.

On the bottom it has a micro USB port for charging. Once charged, it lasts for weeks.

It’s just a prototype yet. I want to build an open-source version with easy to source parts and a 3D-printable case.

bicycle light

I find two things always more complicated than anticipated in weekend projects: power supply and enclosure. For this project I took the battery and charging circuit from an old bicycle light that I had lying around. An empty screw box became the enclosure.

The rest is a white high-power LED, an Arduino Nano (most parts removed except for crystal and micro controller), three buttons, and a 32x128 OLED display.